Electric-arc lamp.



No. 662,996. Patented Dec. 4, I900. J. J.'WO0D.

ELECTRIC ARC LAMP.

. Application filed Dec. 4, 1899 (No Model.) 7 Sheets-Sheet l.

WITNESSES:

/ INVENTOR:

By his Af/omeys.

No. 662,996. Patented Dec. 4, I900.

J. J. woun.

ELECTRIC ARC LAMP.

pplimidn and Doc. 4. 1899.) (No Model.) 7 Sheets--$heet 2.

FIG 4 \k 5 a v 6 A 1 i D L, iii J C B *2 2 I d M e 6 7 6,

4 F/G. 7. i

1:6 a K o O o '5-T vt/i Q l.

ITNESSES: INVENTOR:

1 M By /z1' Azzm'neys.

No. 662,996. Patented Dec. 4, I900. J. J. WOOD.

ELECTRIC ARC LAMP.

(Application filed Dec, 4, 1899) (IuModeL) 7 Sheets-Sheet 3,

By his Aziomejs.

WWI/l/Il/d 7R: Nana's FETER$ co, moroumo" WASHINGTON n c Patented Dec. 4, I900.

J. J. WOOD.

ELECTRIC ARC LAMP.

(Application filed Dec. 4. 1899.)

7 Sheets-$heet 4.

(lo Model.)

FIG. 70,

FIG,. 77.

WITNESSES:

alla

W Ill/M/I/IJEVA No. 662,996. Patented Dec. 4, I900.

- J. J. WOOD.

ELECTRIC ARC LAMP.

(Applicltiun Med Dec. 4, 1899.) (No llodol.) 7 Sheets-Sheet 5.

FIG, 72.

INVENTOR:

- W 77M, WITNESSES:

I B W y Azzomeyx,

m: News un-s co. wornumu, WASMNGTDN, n. c

Patented Dec. 4, I900.

J. J. WOOD.

ELECTRIC ARC LAMP.

(Application filed Dec. 4, 1899.)

7 Sheets-Shoat 6.

(No Model.)

FIG. 77..F/G, 78,

INVENTOR:

By his Attorneys. gm m W6C No. 662,996. Patented Dec. 4, 1900.

J. J. WOOD.

ELECTRIC ARC LAMP.

(Application filed Dec. 4. 1899.)

(No Model.) 1 Sheets-Sheot 7.

INVENTOR:

By Azzomeys, M 53mm WITNESSES:

Unit

JAMES J. \VOOD, OF FORT WAYNE, INDIANA.

ELECTRlC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 662,996, dated December 4, 1900.

Application filed December 4, 1899. Serial No. 739,111. (No model.)

To all whom it may concern.-

Be it known that LJAMES J. WVOD,a citizen of the United States, residing at Fort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Electric-Arc Lamps, of which the following is a specification.

This invention relates chiefly to arc-lamps adapted to be installed serially on a circuit carrying a constant current, but is not confined thereto. a

The principal object of the invention is to render the feeding extremely sensitive, in order to maintain the arc of uniform length and to avoid any material fluctuation in the energy expended in the lamp. Ordinary constant-current arc-lamps designed to absorb fifty volts have a range of variation in feeding of from five to ten volts, or even more. By my invention the extreme range is reduced to three volts, and under normal conditions the variation is less than one-fourth of a volt, being so small as to be imperceptible upon a volt-meter.

Another object of the invention is to economize as far as possible the energy necessarily expended to produce and maintain the separation of the carbons.

A further object to cheapen and simplify the mechanism as far as is consistent with the foregoing conditions and to render its operation as exact and certain as possible under all conditions.

A further object as applied to a clutchfeed lamp is to render the clutch as sensitive as possible in its gripping and releasing action, so that in normal feeding the clutch shall act practically as a friction brake, through which the feedrod is almost constantly descending at a rate almost exactly proportioned to the rate of consumption of the carbons.

The invention further provides novel features and details of mechanism, which will be fully hereinafter described.

The accompanying drawings show the p referred embodiment of my invention as plied to a clutch-feed lamp adapted for burning a single pair of carbons of preferably large diameter.

Figure 1 is a perspective view of the lamp on a small scale. Fig. 2 is a vertical mid-section, and Fig. 3 is a similar vertical mid-section viewed at right angles to Fig. 2. Fig. 4 is a vertical section of the lamp mechanism, on a larger scale, viewed from the same direction as Fig. 2, the section being cut on the line 4 t in Fig. 6, the mechanism being shown in the inert position before turning on the current. Fig. 5 is a view on the same scale as 4, viewed in the same direction as Fig. 3, the section being on the line 5 5 in Fig. 6. Fig. 6 is a horizontal section on the line 6 6 in Fig. 4t, the inclosing case or shell being omitted. Fig. 7 is a section similar to Fig. 4, but showing the mechanism in a different positionnamely, in the normal feeding position. Figs. 8, 9, 10, and 11 are sec1ionalelevations, on a larger scale, showing the lamp mechanism in four successive positions. Fig. 12 is adiagrammatic elevation of the main parts of the lamp, showing the circuit connections. Fig. 13 is a side elevation, and Fig. 14 plan, of the feeding-lever. Fig. 15 is a side elevation, and Fig. 16 a plan, of the retractor. Fig. 17 is a side elevation, and Fig. 18 a front elevation, partly in section, of the bridge-piece or fulcrum lifter connecting the separating armature with the feeding-lever. Fig. 19 is a side elevation, and Fig. 20 a plan, partly in section, of one of the cutout contacts. Fig. 21 is a side elevation, and Fig. 22 a front elevation, of the other contact. Fig. 23 is a vertical mid-section, and Fig. 24- is a rear elevation, of the iron frame of the separating-magnet. Fig. 25 is a section on the line 25 25 in Fig. 26, and Fig. 26 is a plan, of the separating-magnet armature. Fig. 27 is a rear elevation, and Fig. 28 is a vertical mid-section, of a modification of the separating-magnet frame and armature. Fig. 29 is a fragmentary side elevation of a portion of the lam p mechanism, showing the parts in the sameposition as in Fig. 7. Figs. 30 to 33 show the improved feeding-clutch, Fig. 30 being a side elevation, Fig. 31 a plan, and Figs. 32 and 853 plans of the clutch barrel and lever, respectively. St is an elevation of the feed-rod, showing the touch-points of the clutch; and Fig. 31- is a similar View showing a modified arrai'igement. Fig. 35 is a vertical section of the positive-carbon holder or clamp. 36 is a horizontal section thereof. Fig. 37 is an enlarged diagrammatic horizontal section in the plane of cont-act. Fig. 38 is a fragmentary vertical section on the line 38 38 in Fig. 36. Figs. 39 and 40 are diagrams illustrating modifications and corresponding to Fig. 12.

In this lamp I employ separate magnets or solenoids for separating the carbons and for feeding. These 1 will for convenience designate, respectively, as the separating-mag net and the feeding-magnet. The armatures or movable members of these magnets are both connected to a lever, which I will call the feeding-lever and which in turn is connected to the feeding devi e, which is preferably a clutch, in order to communicate to the feed-rod the movements of either armature for the purpose, initially, of lifting the feed-rod to separate the carbons and draw the arc, and subsequently, in the normal operation of the lamp, of controlling the feed of the carbons together to compensate for-their consumption. A resistance-coil is provided, arranged as a shunt, short-circuiting both magnets and cut in or out by a contact device operated under certain conditions by either magnet.

. Referring to the drawings, let A designate the mechanism-case of the lamp; l3, the pendent or drop frame thereof; C and D, the upper and lower or positive and negative carbons, respectively; E, the feed-rod for the upper carbon; F, the clamp therefor; G, the holder for the lower carbon; II, the globe, and l the globe-holder.

The mechanism-case A. is constructed, as usual, with an inner frame comprising top and bottom plates a and Z), respectively, connected together by any convenient posts or upright frames 0 c, as usual, the frame thus formed being insulated in any suitable manner from the exterior portions of the mechanism-case. Within this frame are the magnets and the feed mechanism.

K is the separating-magnet, 71; being its armature or movable member, and M is the feed-magnet, preferably a solenoid, on being its movable member, armature, or solenoid, core. The separating-magnet K is wound with coarse wire and is installed in the main circuit with the carbons, being commonly called the main magnet or coarse-wire magnet. The feeding-magnet is wound with fine wire and is arranged, as usual, in a shunt around the are, being sometimes called the linewire magnet or shunt-magnet. Ignoring for the present the special construction of these magnets, 1 will proceed to describe their connection with the operating mechanism.

The armature or movable member it of the separating-magnet is pivoted at one end and at the other or free end is connected by a link or connectingbar J, which I will call the bridge-piece, to one end of the feeding-lever L. The opposite end portion of this lever is connected to the armature m of the ;t'ecding-magnet M and to a retracting device or retractor which exerts a stress opposing the attraction of such arn'lature. The le-- ver L, between its points of connection with the bridge-piece J and armature m, is connected to the feeding device, which as a whole I will designate by the letterN. This feeding device is preferably a clutch, which in general is or essentially may be of any type usual in arc-lamps, but is preferably of the general construction heretofore used in the food clutch-feed lamps. This connection is effected by means of a link (Z, joined at its upper end to the lever L and at its lower end to the cluteh-levere of the feeding-clutch. This lever has a tail or opposite arm 0, adapted to be engaged by a stop or abutment f, as heretofore, and is pivoted at e to cars on the clutch sleeve or barrel N, and to the lever is pi voted a contact-piece or cl utch-shoe c, which is adapted to bear against the feed-rod. So far as concerns the generic features of my invention any other clutch may be substituted.

By reason of the clutch connection (Z engaging the lever L at a point between its connections with the feed-magnet armature on the one hand and the separating-magnet armature on the other any movement of either armature is communicated through the lever to the clutch.

The retractor for the feeding-magnet armature preferably engages this armature through the medium of the lever by means of a link g, jointed at one end to an arm L of the feeding-lever and at its other end to one arm of a retractor-lever O, the opposite arm of which receives the pull of a retractingspring S, the tension of which is adjusted by a screw g, passing through any fixed part of the frame, as a cross-bar on one of the uprights 0, and on which screws an adjustingnut 9 by which the screw can be propelled up or down. \Vhen the lamp is inactive, as in Fi 8, the spring 8 draws the lever 0 until its long arm is stopped against the top plate a, whereupon the upper joint of the link g becomes a fixed point, and the lever L is suspended therefrom through the medium of the link g.

The retractor has the peculiar function of exerting against the armature or movable member of the feed-magnet a r tractile stress which diminishes as the armature is drawn toward the magnet, as will be hereinafter explained.

The lamp is provided with a resistanceshunt R, consisting, as usual, of a coil of wire connected in a shunt short-circuit-ing the carbons and magnets. this shunt is peculiar. One terminal of the shunt is connected permanently to one lampterminal'for example, to the negative binding-post, as shown in Fig. l2while the other end of the shunt is connected to what I will call a shunt -,ontact-piecep, which in its preferred form is shown detached in Figs. 21. and ignoring for the present the specific construction of the cut-out contacts I will say The cut-out controlling that the shunt contact-piece is adapted to be touched by a contact-piece carried by the armature 7c of the separating-magnet in order that the attraction of this armature shall break the sh nut-circuit and direct the current through the carbons before separating them. Cutout contacts are also provided, so that upon an abnormal excitation of the feedingmagnet M the lamp is short-circuited through the shunt R. Separate pairs of cut-out contacts might be provided for these two operations; but preferably the same shun tcontact 19 is touched on the one hand by a contact 7c on the armature 7% (preferably in theform of a roller, as shown in Fig. 26) and by a contactpiece ,(shown separately in Figs. 19 and 20,) and which is moved down so that it touches the shunt-contact 2) upon an abnormal inclination of the feeding-lever L. In the preferred construction the shunt contact-piece p is formed with a bend 13, into which the end of the shnut-wire or flexible cable B may be soldered, and with one or more (preferably two) laterally projecting curved or spoon -shaped contact-arms p and an upwardlyprojecting contact-arm 19 This contac t-piecep is preferably carried on the bridgepiece J, although it must be insulated therefrom. I attach it to the cross-barj of this bridge-piece, Fig. 18, by means of screws entering the holes in this bridgepiece, insulating bushings being interposed between the screws and the corresponding' holes in Fig. 22. The arms 19 project beneath the contact-roller 7c on the armature, which roller is preferably mounted on a pin k Fig. 26. Preferably the armature is connected to the bridge-piece J through the medium of the pin le the ends of which project through slots Fig. 17, in said bridge-piece, which slots are elongated, as shown in Fig. 29, so as to give suflicieut lost motion for operating the cut-out contacts 7519 In the preferred construction the coutactpiece q is also carried by the bridge-piece J, but is not insulated therefrom, being connected thereto by a frictional pivotal connection, which is simply effected by turning up ears g, which project between the upper arms of the bridge J and have pivot-holes which coincide with the holes jj, Fig. 18, in said bridge, and which are entered by the pivot-screws Z, (shown in dotted lines in Fig. 14,) by which the lever L is pivoted to the bridge-piece J. The cars q are made yield ing, so as to press outwardly against theinner faces of the bridge-piece, and to increase the frictional connection the metal surrounding the pivot-holes is punched outwardly in conical form, as shown at 1 Fig. 20, and projects into and engages frictionally correspondingly-coiled faces formed on the bridgepiece surrounding the pivot-holes. The contact-piece (1 thus makes metallic conductive contact with the bridge-piece and is so fric iioually connected therewith as to retain any position to which it is moved, while offering but slight resistance to any effort to swing it around the pivotal center. Itis formed with a lower arm (1 projecting downwardly and terminating in the contact-face for touching the arm piand with an upper arm q, and the lever L is provided with a cross-bar Z, which enters between the arms g and q, in the manner shown in Figs. 8 to 11, so that an upward movement of the lever may cause the bar Z to lift the contactpiece q or a downward movement thereof may cause this bar to press down the contact-piece.

To moderate the movements of the arma' tures of the respective magnets I provide some suitable retarding devices, preferably dash-pots. In the preferred construction a dash-pot h is provided for the armature 7e and a dash-pot h is provided for the armature m. The daslrpot 7b is not connected directly to the armature 7t,bntis connected to the bridgepiece J, which latter is formed with ears 1L2, Figs. 17 and 18, for this purpose. The dashpot h is connected, preferably, to the armature on through the medium of the lever L, the arm L of which is prolonged and engages at its end with the dash-pot, as shown.

The lamp is provided with any suitable binding-posts, such as those shown at P P in Fig. 5, to which the circuit-wires are connected. I have shown the post P connected metallically to the top plate a, which in turn is connected through springs t'with the feedrod E, the circuit being normally completed through the carbons, and from the lower-carbon holder G by wire 11, which passes up along the frame, as usual, and is joined to the winding or coil of the magnet 70, the opposite terminal of this winding being carried to the ne ative binding-post P, as shown in the diagram Fig. 12. The winding of the feed magnet M is connected in a shunt i between the top plate a and the wire '21, (see Fig. 12,) so that the current flowing through this sh nut joins that trm'ersing the winding of the separating-magnet. When the lamp is cut out through the resistance R the current passes from the top plate a through the magnett'rame K and armature 7t" and through contacts 7t" and 3 into the resistance-shunt, and thence to the negative binding-post. Then the carbons are consumed, the descent of the feed-rod cuts out the lamp in the usual manner by a head or flange pressing down a contact-s n'ing n into contact with another spring at, so as to form a short-circuit between the binding-posts. The same effect is produced by turning the usual switch Q, which swings an arm 9', (see Fig. 12,) connected with the negative binding-post, into contact with a spring 9", connected to the positive bindingpost.

The operation may now be understood. When the lampis inert, or before the cnrreu t is turned on, the lamp mechanism occupies the position best shown in Fig. 8, but shown also in Figs. 2 to 5. On turning on the current the current passes in part through the resistance-shunt R and in part through the carbons and the winding of the separatingmagnet, sufficient current traversing the latfor to energize this ma net, which forcibly attracts its armature until the latter is stopped against the magnetspool. The first effect of this movement is to separate the contact roller R from the COlltttOii-E'LFIDS p whereby the resistance-slnmt is broken. This effectis groduced while the ends f the pin 7& are taking up the lost motion afforded by the elongated slots 7);. soon as this pin strikes the upper ends of these slots the bridge-piece J is lifted, thereby raising the end of the lever L, to which it connects. In this movement his lever swings around its connection with the linl; and hence throu h the link (Z pulls up on the clutch N, causing the ter first to grip the feed-rod and then to move up bodily, lifting the feed-rod and drm ing the arc.

- The upward movement of the bridge-piece J carries one or both of the pivot-screws i into a guiding-notch Pin the manner shown in Fig. 29, so as to stcdy this pivot, which now becomes the pivotal axis or fulcrum around which the feeding-lever L must turn in its future movements under theinliuence of the feeding-magnet. The notch Z is best formed in a hook-shaped guide or bracket 0, 29, which fastened to the upright or post of the case and, if desired, may be made laterally adjustable in order to properly center the armature or soicnoid-core or within the coils or spools of the feeding-magnet The position of the parts at the tern'iination of this lifting movementis shown in Fig. 9. The resistance-shimt it is broken, the carbons have been drawn apart to establish the arc, and the entire current is travcr lug the arc, with the exception of that which is diverted through the coils of the snunt or feeding magnet M; but this in the preferred adjustment is at first insufficient to enable the pull of this magnet to overcome the tension of the retracting-spring S, and hence the retractorlever 0 remains drawn up against the top plate a of the case. Shortly after the lamp has been thus lighted the lengthening of the are due to the consumption of the carbons increases its resistance, and hence increases the impressed electromotive force by which the current is forced through the coil of the feeding-magnet ti, so that the energy of this magnet becomes sufficiently increased to overcome the retractile stress, which begins to pull down its armature, and thereby to rock the retractor-lever O and distend the spring S. In this movement as the armature-lever L turns upon its fulcrum axis at the pivotscrews Z it acts, through the link d, to low-r the clutch bodily, and hence lowers the feedrod and positive carbon, until finally the tail 6 of the clutch-lever strikes the adjustable stop or abutment f, at which instant the normal feeding operation begins. This position of the 1nechanismnamely, that of normal feeding-is shown in Fi 10. After this point is reached any further lowering of the feeding-lever releases the clutch and permits the feed-rod to slide down through it. This feeding movement shortens the are, and con sequently weakens the feeding-magnet, so that the spring draws up the armature-lever, reengages the clutch, and arrests the feed the instant the arc is shortened to the proper length.

By reason of the special construction of the clutch hereinafter described, in connection with the sensitivoness of the feeding mechanism, the feeding action amounts in practice to a variablebrake action of the clutch upon the feed-rod, so that the latter is almost constantly descending through the clutch, the rate of its descent being nicely adjusted to the rate of consumption of the carbons by the action of the feed mechanism, so that the feeding is practically continuous instead of intermittent.

in case the feed-rod should stick in its guides or in the clutch and refuse to feed, the consequent lengthening of the are beyond the normal increases the energy of the feedingmagnet, so that it exerts a stronger pull upon its armature and draws down the lever 1 until the position shown in Fig. 11 is reached. in this downward tilting movement of the lever its bar Z has pushed down the frictionally-mounted contact-piece (1 until the arm (1 thereof in the lowermost osition shown in Fig. 11 makes contact with the arm 1) of the contact-piece p, and thereby again closes the shunt containing the resistance-coil it. This action short-circuits the lamp through the resistance-coil,thereby extinguishing the arc, (since in practice the resistance-shunt has only, for example, about one-fiftieth the resistance of the arc.) Hence the current through the are and the separating-maguet K ceases and this magnet releases its armature 7;, which latter falls by gravity and in its descent first acts to bring its contact-roller 71' against the concave contact-arms p and hence establishes a new closure for the resistanceshunt, after which in continuing its descent the bridge-piece J and fulcrum end of the lever L move down with it, thereby lowering the clutch-lever and freeing the clutch. The shortcircuiting of the are through the resistance-coil is accompanied by the demagnetizing of the feeding-magnet M, whose armature is drawn up by the retractor. Thus the feeding-lever L is moved up at one end and down at the other almost simultaneously, and in this tilting movement the bar 7/, striking the upper arm g of the frictional contactpiece q, tilts the latter upwardly to the position shown in Fi 8, whereby its contact with the piece 19 broken. This movement, however, is unaccompanied by any breaking of the shunt-circuit through it, because the latter is maintained closed through the contacts 7t and p as shown in Fig. 8. The sudden downward movement thus imparted by the dropping of the fulcrum end of the feeding-lever to release the clutch is accompanied With sullicient shock so that it jars the "Feed- 10Cl free, 1hereby insuring Thai this rod shall fall, and by bringing the carbons together reestablishes the main circuit through the Carbons. When this occurs, the current again energizes the separating-magnet K, which immediately retracts its armature, and the lamp is lighted in exactly the same manner as at the outset, thereby reestablishing ihe condition shown in Fig. 9 and repeating the series of operations heretofore described. The operation of relighting occurs instantaneously upon the contacts reaching the cutting-out position shown in Fig. 11, it being understood that Fig. 11 shows a position as sumed at only one instant and immediately followed by the succession of operationsjust described.

In the movements of the armature 7a the dash-pot h performs an important function. In the initial or separating movement the armature moves up without restraint from the dash-pot until ithas taken up the slack or lost motion in the slots 75 after which, by reason of the daslrpot being connected to the bridge-pieceJ, it has to carry the dash-pot with it, and hence the lifting movement that it imparts to the bridge and to the lever L is a comparatively slow movement, which compels the arc to draw slowly and prevents breaking the circuit, particularly when the ligl'ning movement is caused by starting up the dynamo with the lamps switched into circuit and being lighted simultaneously. Du ring the falling movement of the armature 7; the same action of the dash-pot is repeated, in that the armature, at first t'alls without retardation, so as to instantly close the cutout contacts for the resistance-shunt circuit by taking up the lost motion in the slots k after which the further movement of the armature, accompanied by the descent of the bridge'piece J and lever L, is moderated by the dash-pot. Thus the dash-pot holds up the bridge-piece J and prevents its falling ioo quickly, and this insures that the shuntcontacts 7r p shall be closed before the contacts (1 19 are opened, and hence prevents the drawing of an are between these latter contacts during their separation. An impor tant requisite to this end is that the opening of the contacts 19 shall be retarded, for if this opening occurred on the first upward movement of the armature m as the feedinginagnet is demagnetized by the lamp being short-circuited through R it would be liable to occur before the closing together of the contacts 7513 and hence would draw an are which would oxidize and event ually burn out the cut-out contacts g 1 This is avoided by holding the contact-piece q frictionally in place against the contact-piece p uniil the armature 772 has executed a prolonged retract ile movementthat is, until the lever has tilted so far as to strike the upper arm g, and thereby tilt the contact-piece q with it, which gives ample time to enable the armature 7.: to

fall and close together ihe contacts 7; p AuyHuln-r frictional mouniingof' the contactpiece (1 or its equivalent which will leave it where it was moved by the abnormal excitation of the feeding-magnet until it is moved back by some later or retract-ile movement will be within this feature of my invention.

It the arc were blown out, the sudden increase in strength or the feeding-magnet M instantly draws down the lever L to the position shown in Fig. 11, and thereby short-circuits the lamp through the resistance-coil; but the first part of this movement releases the clutch, so that the l'eed-rod instantly be gins to fall and brings the carbons together to reestablish ihe normal circuit. The feedingunagnet is instantly deenergized either by the closing together of the carbons or by the short-circuiting of the are through the resistance-shunt, if the latter shouid occur first, and the retractor pulls up the end of the feeding-lever to which the armature an is connected, so that This iilting movement of the lever (even without any lowering of its fulcrum end) acts to tilt the contact-piece q away from the contact-piece p, and thereby makes the first break in the resistanceshunt, after which, upon the subsequent reenergizing of the separating-magnenthe resistance-shunt is finally broken. The lamp is relighted by the upward movement of the armaiu re 7;, as in the first instance. The proportions are such that the loose contact-piece (1 will be tilted so as to break contact with 1) either by the pulling up of the free end of the lever L without altering the position of its fulcrum or by lowering its fulcrum end without the retraction of its free end.

Having thus made clear the general mode of operation, I will now proceed to describe certain novel features of my invention.

The principal object of my invention is to increase the sensitiveness of the feeding mechanism, so that the feeding movements of the 1 lamp may be accompanied by only a very minute or trifling variation in the energy expended in the lamp. In ordinary arc-lamps, where the feeding-magnet is in a shunt short circuiting the arc,its energy varies according to The variations of impressed electromotive force due to the varying length of the arc, and hence to its varying resistance. hen the arc is too long, this magnet is consequently strengthened and it acts to set the feeding mechanism into operation to impart a feeding movement, which in turn results in shortening the arc, and hence in weakening the feeding-magnet. The result of this mode of operation is that considerable fluctuations occur in the voltage or energy consumed by the lamp. To overcome these fluctuations,

I compensate for the weakening of the mag net as the arc shortens by varying the mechanical advantage at which the spring stress is com municated to the magnet, so that as the armature is drawn to the magnet and the magnet is consequently weakened by the resulting shortening of the arc the retractile force against which it operates shall give way or diminish in so nearly the same ratio as to retain the effectiveness of the magnet.

The tension of the retracting-spring increases as it is distended or otherwise flexed. To overcome this effect and produce the contrary result upon the armature-that is, to cause the retractile stress to diminish with the movement of the armature toward its magnet-the retractor-lever 0 is so devised as to vary the mechanical advantage at which the spring stress is communicated to the magnet, so that the communication of such stress shall be most effective when the armature is fully retracted and shall become progressively less effective during the attracting movement of the armature. To this end I so shape and arrange the retractor-lever O that the relative effective lengths of the two arms of the lever shali vary during themovement of the lever which accompanies the attracting movement of the armature in such manner that the effective length of the arm to which the spring is connected shall diminish proportionately to the effective length of the arm to which the armature is connected. This I accomplish, preferably, by so locating the fulcrum point or axis :2; upon which the lever turns that its point of engagement with the spring shall during the movement of attraction swing upward in an are such that the line of stress of the spring shall during this movement continually approach the fulcrunraxis, and hence shorten the effective length of this arm. The arrangement may be such that the effective length of the other arm to which the armature is connected shall be correspondingly lengthened during this movement, or both effects may occur sinniltaneously. The essential result is that duriugthe movement of attraction the effective leverage of the lever shall change to an extent greater than that suflicient merely to compensate for the increasing tension of the spring as it is distended, so that the retractile stress which is communicated to the armature shall actually diminish during the movement of attraction of the armature. In the construction shown the effective lengths of the two arms of the lever in three different positions thereof are indicated in Figs. 9, 10, and 11 by the double-headed arrow which intersects the axis a, the distance from the axial center to the arrow-tips indicating the effective lengths of the respective arms. From this it will be seen that the ratio varies from approximately 1 to 1.80 in Fig. 9 to 1 to 2.25 in Fig. 10 and 1 to 2.75 in Fig. 11, or, roughly speaking, the spring tension is diminished to almost one-half in 9 and to almost one-third in 11, this ratio of diminution exceeding the ratio of increase of the tension of the spring by reason of its distention. Of course the variation in ratio resulting from the proportioning of the lever must be varied according to the length of the spring, the throw of the armature, and the nature of the feeding-magnet, whereby its coe'l'licient of attraction is varied. With the distinct separating and feeding magnets of my lamp and the feeding-lever arranged as described the retracting-spring forms the solo resistance to the attracting movement of the feeding-magnet. By varying the effective force of this spring, therefore, I cause the entire reiractile stress to vary in the same desired ratio. The practical result of this feature of my invention is that whereas in ordinaryarclamps consuming normally iifty volts the range of variation in feeding is from five to eight volts or more, in my improved lamp, which is designed to feed at forty-live volts, the extreme variation in feeding is than volt and in normal operation is less than one one-fourth of a volt, while a change of three volts will move the armature of the feedingmagnet from its highest to its lowest point, where it operates the cut-ou t.

I design the magnet of my improved lamp to give the maximum lift and to economize to the utmost the electrical energy. To this end lprovide but one air-gap in the magnetic circuit and provide for along range of armature movement with the minimum variation of air-gap. To these ems the magnet K is constructed with a core If? within the coil or winding and an L-shaped frame K outside the coil, as shown, the armature It being pivoted to this outer frame and being formed with a hole through which n'ojects the conoidal end or pole-piece of the core 1U. The hinge is preferably a knife-edge joint, as shown in -l and '7, formed by in-oviding a knife-edge s on the frame K and a groove 5 in the armature, (see Figs. to 26,) so that the armal. ure may have a rocking contact with the knife-edge of the magnet. This construction gives a constant magnetic contact, which when the armature is down is reduced by the angular gap shown in Figs. 1- and 8; but upon the attraction of the armature this gap is closed, as shown in Figs. 7 and 9. By the conoidal head of the pole-piece projecting into the hole in the armature the single magnetic gap at this point is shortened and a long movement is given to the armature, accompanied by a relativelyshort magnetic gap when the armature is retracted. his forms a very powerful magnet that is very economical of energy, so that but little expenditure of electric power occurs in the magnet while the lamp is in use. To hold the hinged end of the armature from fallingaway from the magnet when the latter is deenergized, 1 form it with notches 5 Fig. 26, which are entered by ii -shaped projections s fastened on the frame K, as shown in Figs. :3 and 21-, the heads of which project beyond said notches beneath the lower face of the armature, thus const itutinga cheap and simple form of hinge.

A modification of the knife-edgc hinge-joint for the armature is shown in Figs. 27and 28,

where the magnet-frame K is cut off square at its bottom and has fastened to it a hingeframe 8 having ears 3 turned down at its ends, while the armature 7; has hinge-ears 3 passing freely through holes in these ears and driven or screwed into it. This also forms a cheap and suitable construction of hinge affording a very slight magnetic gap, which diminishes as the armature is attracted.

A further feature of my invention which contributes greatly to the sensitiveness and imiformity of the feeding action relates to the construction of the feeding-clutch. Ordinarily in such clutches the barrel N is simply a tube (in some cases having a grooved inner surface) making a loose fit with the feed-rod, so that the inner surface of the clutch makes contact with an extended area of surface of the rod. l/Vith this old construction there is liability that as the surface of the rod becomes dirty its extended area of contact with the clutch-barrel may cause it to stick therein and interfere with the smooth uniform feed of the clutch. To avoid this disadvantage, I form the clutchbarrel N to contact with the feed-rod at only four points, as clearly shown in Figs. 30 to 3d-namely, at two upper and two lower points. To this end the barrel is hollowed out to a larger diameter than the rod between its top and bottom ends, as clearly shown, for example, in Figs. 5 and9, so that it may be said to be formed with internal flanges it at top and bottom, which alone approach the rod, and each of these flanges is cut away in the manner best shown in Fig. 32, so as to leave projecting portions in contact with the rod at only two points t '6. These contact projections f touch the rod on its side opposite to that against which the clutch-shoe e acts and in planes above and below the shoe. The result is what maybe designated a fivepoint clutch, which touches the rod at points indicated in Fig. 34, where the shaded portions 15 indicate the four positions of contact of the projecting portions t of the clutch-barrel, and the dotted rectangle 6 indicates the position of contact with the opposite side of the rod of the clutch-shoe 6 As the clutchbarrel is guided solely upon the rod and supported solely upon the clutch-lever c, this construction results in a very nice and accurate adjustment of the clutch to the rod with the minimum practicable area of surface contact between the clutch and rod, so that the liability of sticking is reduced to the minimum and any particles of grit or foreign matter which may adhere to the rod are onabled to work through the clutch without interfering with its action upon the rod. The practical result of this feature of my invention is that instead of feeding by a succession of gripping and letting-go movements, so that the feed-rod is first held fast and then permitted to fall and again gripped and held fast, my improved clutch is adapted to feed after the manner of a frictiotnbrakethat is to say, in feeding it does not entirely release the red, but retains a frictional retardation thereupon, so that the rod slowly slides down through the cl uteh at a rate almost exactly proportionate to the rate of consumption of the carbons, thereby rendering the feed practically continuous instead of distinctly intermittent, as heretofore.

For adjusting the tripping-point of the clutch I maize the abutment f adjustable. This abutment is formed as a small metal plate, the upper end of which is preferably bent to project into a slot in the standard f, in which slot. the lever-tail 6 moves and is guided. The abutmentf is fastened to the standard by a screw f engaging the standard and working through a slot in the abutment, as shown, for example, in Fig. 8. To adjust the abutment, the screw is loosened and the abutment is set up or down, its hooked end serving to keep it vertical, and the screw is retightened.

The positive-carbon clam p F is preferably of the construction best shown in Figs. 35 and 36. It has a stem Lt, which may be screwed or otherwise attached to the lower end of the feed-rod E, and from this stem or attachment it is formed with a downwardlyprojectiug shell or arm a, which lower down merges into a ring F of peculiar shape, a set screw or thumb-screw a being provided to clamp a carbon within this ring in the manner shown in Figs. 2 and 3 and Figs. 35 and 36. The ring F is preferablv oval in crosssection, as shown in 35, although its exterior contour is immaterial. Internally the ring is egg-shaped in plan (see Fig. and convex in cross-section, as shown in Fig. 38, which latter is an enlarged cross-section in the oblique vertical plane, (indicated by the line 33 38 in Fig. 36.) Hence the ring presents two points of contact with the cylindrical carbon C-namely, where its inner surface, which is concave in a horizontal plane, tangents the circumference of the carbon, as shown in thediagram Fig. 37, the tangenting-points being marked y y in that figure. As its inner surface is convex in a vertical plane it tangents the cylindrical surface of the carbon in the manner shown in Fig. 38, where y is the iangentingpoint. lhe carbon is held against these tangent-points by the set-screw 11?, which is tightened against it in such manner that the carbon is gripped at three points as nearly equidistant as possible. 3y reason of the points 'y y being on concave curves the carbon is at these points gripped with as little abruptness as possible, and hence with the minimum liability of breakage, and the curves compensate for any slight variations in the diameter of the carbon that may occur in practice. By reason of the contact-points being made with curves in vertical planes (see Fig. 38) the carbon is gripped as gently as possible, while affording means for compensating for crooked carbons bybringing the lower end of the carbon to its 8 ceases proper position in the vertical axis at the expense of tilting or cauting the upper end, where it is grippel in the clamp, this tilting being indicated to an o: iggerated degree by the dotted line in. big. This simple construction of clam p affords th us a universal adjustment for the carbon without the provision of any moving p: rt in the clamp except the thumb-screw thereof.

The lower or negative carbon D is held in a clamp G of usual construction, consisting of a tubular standard o, projecting up from its insulated attachment to the globe-holder i and provided at its u r end with a loose clamping; go,drawn agai" thecarbon by a thumb-screw The tube o is open at its bottom end to nable the carbon to thrust up through it from beneath. t desirable to enable full-length carbons to used as the lower or negative carbons, which requires that th surplus length shall project beneath when a fresh carbon inserted, the halfburned negative carbon being raised when a new positive carbon is inserted in the lamp. Figs. 2 and 23 show the condition at, for example, the end of the first nights run, the upocr carbon being consumed and the lower being burned down nearly to the holder To pre 'iare for the second nights run, the trinr mer will place a new upper carbon in the posi' tive holder or clamp I and will raise the lower carbon D, so that its bottom end will be gripped by the clamp G. it is necessary to house the protruding portion of the negative carbon projecting beneath the globe-holder l, and for this purp se it has been usual to pro- 'ide a long 'iisulatcd tube, a construction which has been expensive and fragile and has sometimes caused accidents through carbon-dust or other conducting particles getting into the tube and making an electrical connection between the carbon and the tube. I avoid these disadvantages and provide a simpler and cheaper construction by forming he usual dust cag T with a tubular downward extension T, formed, preferably, integrally with it, s one casting. This tubular extension "l" is so much larger than the carbon that there is no danger of contact, while any particles of dust that may fall into it are given free escape through a bottom opening 20, which also will drain off any moisture that will enter the cup, and also provides a venti lating-inlet through which air may ascend along the carbon and passing through the dust-ca} and through the usual openings in the globe-holder may enter the globe. Any dust falling from the globe will drop through the openings in the globe holder and be caught in the dust-ca T, an upuutrdly-projectin annular flange 4v boim provided to prevent this dust from entering the tubular extension 'l". in trimming the lamp the dustcap T is removed in the usual manner for emptying it of any ust which may have fallen into it, and this act uncovers and cxooses the negative carbon.

The globe-holder i may be provided. with auysuitablc moans fol-engaging on its under side with the d ustcap 'l and on i s upper side with the globe. Such provisions are shown in my Patent No. -.i2ll,i05, dated April 22, 18530.

The lamp may be supported in any suitable way, the SHppOl'lJ shown, which forms no part of my invention, consisting oi a socket U, screwed to the outer lop plate of tho mechanism-case and connected through an insulating-bar U, of wood or other material, with a metal hood U which fastened to a supporting arm or bracket.

The inec'nanism-case, although in general ordinary constructimi, presents a novel ature designed to make the case fit more tightly without increasing; the dil'liculty oi. appl ing its shell. The case has the usual cast top plate A, by which the entire lamp is supported, and to which the inner Frame is fastened through insulating connections, this top plate having an outer pendent flange .2. The case is inclosed, as usual, by a sheet-metal the upper end of which his within shell i:

liange .2, while its lower end is centered by and supported against a projecting insulating dish or ringb, fastened beneath the bottom plate 1) and projecting beyond it. I nowforin the shell A with an inturued bead or rib .2" at such level that when in place it meets and rests against the projecting edge of the dish l), as clearly shown in Fig. :11. This bead contracts the diameter of the shell at this level and makes a tight and moisture and dust proof connection between the shell and this insulating-disk. If the entire shell be contracted to this diameter in order to make such complete connection, it would be exceedingly dillieult to push this shell up into place, especially after the swelling or waroing of the ring b, which often occurs after a short usage of the lamp; but by making the shell of large diameter, so that it will easily pass the disk 1) until its upper end has been inserted into the flange .2, the shell is very easily pushed up into place and its tightly only when the bead .2" comes to its bearing against the dish or insulating projoe tion I).

It must not be inferred from the particularity of detail with which I have described the preferred embodiment of my invention that I am by any means limited to this one embodiment thereof, since, in fact, my invention is capable of being embodied in various mechanical constructions. Those features which are believed to be essential to my invention in its generic and specific aspects I have endeavored to deiiue in the claims hereinafter contained.

As examples of the modifications of which my invention is susceptible, I may mention that the cutout contacts for closing the sh untcircuit ft may be greatly varied in arrangement, two possible modifications being shown in Figs. 39 and L0. in Fig. 39 the contact 7;, in stead of being a roller carried by the armature 7c, is an arm carried at the top of the bridgepiece J and touchingacontact-spring nwhivh in this case is fastened on, but insulated from, the lever L. The lost-motion connection is in this instance made between the bridge J and theleverLby providing the fulcr u m-pin Zwith a slot in which to work. Hence the retarding device, (the dash-pot 72,) instead of beii'ig connected to the bridgepiece J as before, is here shown as connected to the lever L at near the fulcrum end thereof. The cut-out contacts for closing the resistance-shunt upon an abnormal excitation of the feeding-magnet M are also differently arranged,consisting of a contact-arm g carried by the level-L and touching a contact 19 mounted on a fixed support. The contacts p and p are connected to the resistance-coil R. The contactarm g is connected by a frictional joint to thearmaturelever at Z so as to retain any position relative'ly to the lever to which it is turned. On the downward movement of the lever a projection b on this arm encounters a fixed pin 5 whereby the contact-armis tilted into contact with the fixed contact 19 During the upward movement of the lever contact is maintained until the inclined face of the arm g strikes the stop 19 and tilts it away from p; but before this occurs the falling of the armature 7t has brought the arm 7t against the spring 1). In Fig. 40 the bridge-piece J, instead of constituting a link arranged vertically, constitutes a lever arranged horizontally as an extension of the armature 7t, and the lost-motion device consists of pins Z Z", between which one arm of this lever may vibrate. In the upward movement of the armature k the lever J is first turned around the fulcrum-pin Z until it strikes the pin Z in which movement its contact end it parts from the contact-spring p, which in this instance is fixed to, but insulated from, the armature 70. When the lost motion has thus been taken up, the lever J becomes a fixture of the armature and lifts the fulcrum-pin Z, and hence lifts the lever L, the motion of which is retarded by the dash-pot it. When the armature it falls, its first movement takes up the lost motion by turning the leverJaround the fulcrum-pin Z until it strikes the lower stoppin Z during which movement its end touches the contact-spring p. The cut-out contacts for closing the shunt R upon an abnormal excitation of the feedinganagnet consist of a fixed contact-spring p and a movable contact-piece g, which latter is frictionally pivoted at Z to any fixed part and is tilted by a pin m, projecting from the armature m of the magnet, which upon the abnormal excitation of the magnet acts against a lower toe o to press down the contact-piece against 1), and subsequently upon the retraction of the armature strikes the upper toe c to lift the contact-piece out of contact with 13 The feeding'clutch N may be modified to arrange its contact points in the manner shown in Fig. as, where instead of the two lower contact-points l of Fig. 34 one lower coniact-poinl If is provided, so that the barrel touches one side of the feed-rod at two points above and one below the level of contact with the opposite side of said rod of the shoe 6 or the two contacts might be arranged below and the one above, as if Fig. 345 were inverted to like effect. The one contactpoint is effected by forming the barrel with a single inward projection, (shown in dotted lines at I? in Fig. 32

I claim as my invention the following-defined novel features, substantially as hereinbefore specified, namely:

1. An arc-lamp having distinct separating and feeding magnets, a lever connected at its normal fulcrum-axis to said separating-mag net and operated by said feeding-magnet, a resistance-shunt around the arc, and a cutout adapted to be operated solely by the excitation of the separatingmagnet to break said resistance-shuntindependently of movements of the feeding-magnet.

2. An arc-lamp having distinct separating and feeding magnets, a lever connected at its normal fulcrum-axis to said separating-magnetand operated by said feeding-magnet, and a eut-out operated by an abnormal excitation of said feeding-magnet, whereby said cut-out is operated independently of movements of said separating-magnet.

3. lln an arc-lamp, the combination with distinct separating and feeding magnets and a resistance-shunt, of a lever connected atits normal fulcrum-axis to said separating-magnet and operated by said feeding-magnet, and a cut-out operatively connected to said magnets for closing said shunt upon either an abnormal excitation of the feeding-magnet, or a demagnetization of the separating-magnet.

4. An arc-lamp having distinct separating and feeding magnets, afeeding device, a feeding-lever connected at its normal fulcrumaxis to the separating-magnet, connected for normal operation to the feeding-magnet so as to be moved by either magnet, and connected at an intermediate point to said feeding device to communicate the movement of either magnet thereto, a resistanceshunt, and a cut-out therefor operatively connected to said magnets for closing said shunt upon either an abnormal excitation of the feeding-magnet or a demagnetization of the separating-magnet.

5. An arc-lamp having distinct separating and feeding magnets, afeeding device, a feeding-lever connected at one end to the separating-magnet and at the other end to the feeding-magnet so as to be moved by either magnet, and connected to said feeding device to communicate the movement of either magnet thereto, a resistance-shunt, and cut-out contacts therefor operatively connected to the separating-magnet, and means whereby the excitation of said magnet first separates said contacts and thereafter communicates motion to said lever.

6. An arc-lamp having distinct separating and feeding magnets, a feeding device, a feeding-lever Connected at one'end to the separating-magnet and at the other end to the feeding-magnet so as to be moved by either magnet, and connected to said feeding device to communicate the movement of either magnet thereto, the connection between said lever and separating-magnet being made through a lost-motion device, a resistance-shunt, and cut-out contacts therefor operatively connected to the separating-magnet Within the limits of said lost-motion device, whereby the first movement of said magnet operates said contacts until the lost motion is taken up, and thereafter is communicated to said lever.

7. An arc-lamp having distinct separating and "feeding magnets, a feeding-lever connected to said magnets at different points, a resistance-shunt, and two cut-outs therefor operatively connected to the respective magnets, so that the one is operated by movements of said separating-magnet, and the other by extreme movements of said lever around its point of connection with said separatingmagnet.

8. An arc-lamp having distinct separating and feeding magnets, a lever connected at its normal fulcrum-axis to said separating-magnet and operated by said feeding-magnet, a resistance-shunt and two cut-outs therefor operatively connected to the respective magnets, so that the one is operated by movements of said separatingmagnet, and the other by extreme movements of said lever around its point of connection with said separating magnet.

9. An arc-lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, a resistance-shunt, and cut-out contacts therefor comprising an insulated contact-piece, a contact operatively connected with said separating-magnet to break contact with said insulated piece upon the excitation of said magnet, and a contact-piece connected with said lever to be moved by extreme movements thereof around its point of connection with the separatingmagnet, both said contacts adapted to touch said insulated contact-piece for closing said resistance-shunt.

10. An arc-lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, a resistance-shunt, and cut-out contacts therefor comprising an insulated contact-piece, a contact connected with the armature of said separating-magnet, and a contactpiece connected with said lever to be moved by extreme movements thereof around its point of connection With the separating-magnet, both said contacts adapted to touch said insulated contact-piece for closing said resistance-shunt.

11. An arc'lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, its connect-ion With said separating-magnet being made through a lost-motion device, whereby the initial movement of said magnetwill take up the lost motion thereof before moving said lever, a retarding device for retarding the movement communicated to said lever, a resistance-shunt, and a cut-out therefor operated by said initial movement while taking up such lost motion.

12. An arc-lamp having distinct separating and feeding magnets, a lever L connected thereto at different points, a bridge-piece J connecting the armature of said separatingmagnet to said lever, a resistance-shunt, and cut-out cont-acts therefor comprising a contact-piece fixed to said bridge-piece, and a contact on saidarmatureadapted to touch said contact-piece.

13. An arc-1am p havingdistinct separating and feeding magnets, a lever L connected thereto at different points, a bridge-piece J connecting the armature of said se 'laratingmagnet to said lever, a resistance-shunt, and cutout contacts therefor comprising a coin tact-piece 2) fixed to and insulated from said bridge-piece, and a contact on said armature adapted to touch said insulated contact-piece.

14. An arc-lam p having distinct separating and feeding magnets, a lever L connected thereto at different points, a bridge-piece J connecting the armature of said separatingmagnet to said lever and having a lost-motion connection with said armature, a resistanceshunt, and a cut-out thereforcomprising a contact-piece fixed to said bridgepiece, and a contact on said armature adapted to make or break contact with said contactpiece during the movements of said armature in taking up lost motion.

15. An arc-lamp having distinct-separating and feeding magnets, a lever L connected thereto at different points, a bridge-piece J connecting the armature of said separatingmagnet to said lover, a resistance-shunt, and cut-out contacts therefor comprising a contact-piece 1) fixed to said bridge-piece, a contact on said armature adapted to touch said contact-piece, and a contact-piece q frictionally mounted and adapted to be moved into or out of contact With said piece p by extreme vibratory movements of said lever.

16. An arc-lamp having distinctseparating and feeding magnets, a lever L connected thereto at different poi n ts, a resistancc-shu nt,

and cut-out contacts therefor comprising a contact-piece and a contact-piece q, the latter frictionally mounted and adapted to be moved into or out of contact with the piece 1') by extremeangular movements of said lever.

17. An arc-lamp having distinct separating and feeding magnets, a lever L connected thereto at different points, a resistance-shunt, and cut-out contacts comprising a cont-actpiece 19 and a contact-piece q, the latter frictionally pivoted at the point of connection between said lever and separating-magnet, and adapted to be moved into or out of contact With the piece by extreme angular movements of said lever.

18. An arc-lamp havingdistinct separating and feeding magnets, a lever L connected thereto at different points, a bridge-piece J connecting the armature of said separatingmagnet to said lever, a resistance-shunt, and cutout contacts therefor comprising a contactpiece connected to said shunt having a concave contact-arm p and a contact on the armature 7c ofsaid separating-magnet consist ing of a roller adapted to touch said concave arm.

19. An arc-lamp feeding-magnet combined with a retracting-spring, and an interposed lever adapted to vary the mechanicaladvantage at which the spring stress is communicated to the magnet, in such manner as to render such stress most effective when the armature is retracted, and progressively less effective as the armatn re is attracted.

20. An arc-lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, and a retracting -spring for the feedingmagnet adapted to diminish its retraetile stress during the attracting movement of said magnet.

21. An arc-lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, a feeding device connected to said lever at an intermediate point, and a retracting-spring for the feeding-magnet adapted to diminish its retractile stress during the attracting movem ent of said magnet.

22. An arc-lamphavingdistinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, a feeding-clutch connected to said lever at an intermediate point so as to be moved by either magnet, and a retracting-spring for the feeding-magnet adapted to diminish its retractile stress during the attracting movement of said magnet.

23. An arc-lamp having distinct separating and feeding magnets, a feeding-lever connected to said magnets at different points, a retracting-spring for the feeding-magnet adapted to diminish its retractile stress during the attracting movement of said magnet, aresistance-shunt, and cut-out contacts for closing said shunt arranged to be operated by an ab normal attraction of said feeding-magnet.

24. An are-lamp having distinct separating and feeding magnets, and a feeding-lever connected at its normal fulcrum-axis to said separating-magnet and connected for normal operation to said feeding-magnet, said separating-magnet being constructed with a magnetic circuit having only one gap, the armature thereof being hinged at one end, said gap existing between the free end of said armature and the pole-piece of the magnet, and the armature having an opening through which the pole-piece projects.

25. An arc-lamp having distinct separating and feeding magnets, and a feeding-lever connected to said magnets at different points, said separating-magnet being constructed with a fixed frame and an armature hinged at one end to said frame, and free to move at its other toward the pole-piece of the magnet, its hinge-joint shaped to diminish the magnetic resistance of said joint during the movement of attraction.

26. An arc-lamp having distinct separating and feeding magnets, and afeeding-leverconnected to said magnets at different points, said separatingmagnet being constructed with a fixed frame and an armature hinged at one end to said frame with a hinge-joint having an angular gap when the magnet is tin-attracted and arranged to close said gap by the attracted movement of said magnet.

27. An arc-lamp having distinct separating and feeding magnets, and a feeding-lever connected to said magnets at different points, said separating-magnet being constructed with a fixed frame and an armature hinged at one end to said frame with a knife-edge joint, the frame being formed with a knife-edge and the armature with a groove receiving it and leaving an angular gap when the magnet is unattracted, and arranged to close said gap by the attracted movement of said magnet, and a projection on the frame loosely ei'igaging the armatn re to prevent its dropping off when unattracted.

28. In an arc-lamp, a feeding-clutch having its barrel cut away internally to reduce its contact with the feed-rod to a plurality of points of contact on the opposite side from the shoe, and having not more than two contact-points arranged on one side of the horizontal plane of the middle of said shoe, and one or more contactpoints on the other side of said plane.

29. In an arc-lamp, a feeding-clutch having only five points of contact with the feed-rod, namely the shoe on one side of the rod, and two pairs of contact-points on the other side thereof, arranged above and below the level of said shoe.

30. A carbon-clamp for an arc-lamp comprising an elliptical ring having three points of contact with the carbon, one a clampingscrew, and the others formed in the ring as surfaces convex in vertical planes and concave in horizontal planes and making tangential contact with the cylindrical surface of the carbon.

31. In an arc-lamp, a tubular negative-carbon holder adapted to let the carbon project beneath it, combined with a dust-cup having a tubular extension adapted to inclose the pendent portion of the carbon.

32. In an arc-lamp, the drop-frame formed with a globe-holder, a tubular negative-carbon holder adapted to let the carbon project beneath said frame, and a dust-cup fitting beneath said globe-holder, having a tubular extension adapted to inclose the pendent por tion of the carbon, and extended up within the cup to prevent dust falling into it.

In an arc-lamp, the mechanism-case having top and bottom plates, the latter be- IIO ing of insulating material and a shell A said shell being formed with an internal bead to make a close fit with the annular projection b of the bottom plate.

34. An arc-lamp having distinct separating and feeding magnets, and a feeding-lever connected to said magnets at different points, a bridge-piece for connecting the normal fulcru m-axis of said lever to the separatingmagnet, and a guide having a notch or recess for properly locating such fulcrum-axis during its movement by said magnet.

35. An arc'lamp having distinct separating and feeding magnets, a resistance-shunt, and a cut-out therefor, means for operating said cut-out to close said shunt by an abnormal excitation of said feeding-magnet, and means for maintaining a closure of said shunt beyond the period of such abnormal excitation.

36. An arc-lamp having distinct separating and feeding magnets, a resistance-shunt, and a cut-out therefor, means for operating said cut-out to close said shunt by an abnormal excitation of said feeding-magnet, and means for maintaining said shunt closed until the completion of a normal retractile movement of said magnet.

37. An arc-lamp having distinct separating and feeding magnets, a resistance-shunt, and out-out contacts therefor operated to close said shunt by an abnormal excitation of said feeding-magnet, one of said contacts frictionally mounted to retain any position to which it is moved, and connected to said feedingmagnet to be moved upon an abnormal attraction thereof, and upon a retraction thereof, to maintain a prolonged closure of said shunt between said movements.

38. In a clutch-feed arc-lamp, the combination with a clutch-lever of a fixed abutment for limiting its upward movement and an abutment for tripping the clutch, consisting of a plate fastened by a set-screw and vertically adjustable.

39. In a c1utch-feed arclamp, the combination with a clutch having a clutch-lever, of a standard f having a slot in which the tail of said lever may move, and a vertically-adjustable abutment f for closing the lower end of said slot.

40. In a clutch-feed arc-lamp, the combination with a clutch having a clutch-lever, a standard f having a slot inwhich the tail of said lever may move, and a vertically-adj ustable abutment f for closing thelower end of said slot, consisting of a plate bent atits upper end to enter said slot, and having a set-screw for adjustably clamping it to said standard.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

JAMES J. \VOOD.

Witnesses:

FRED S. HUNTING, D. 0. DAVIS. 

